Most current mechanical watches include a Swiss lever escapement. The two main functions of the escapement are:
maintaining the back and forth motions of the resonator, formed by a sprung balance assembly;
counting these back and forth motions.
In addition to these two functions, the escapement must remain robust, and resist shocks, and is devised to avoid jamming the movement (overbanking).
The Swiss lever escapement has low energy efficiency, on the order of 30%. This low efficiency is due to the fact that the escapement motions are jerky, and that several components transmit their motion via inclined planes which rub against each other.
FR Patent 630831 in the name of SCHIEFERSTEIN discloses a method and an arrangement for the transmission of power between mechanical systems and for the control of mechanical systems.
WO Patent 2015104693 in the name of EPFL discloses a mechanical isotropic harmonic oscillator which includes at least one connection with two degrees of freedom supporting an orbiting mass with respect to a fixed base with springs having isotropic and linear restoration force properties, wherein the mass has a tilting motion. The oscillator may be used in a time measuring device, for example a watch.